Ultrasonic diagnostic imaging with nonlinearly intermodulated frequency components

摘要

An ultrasonic diagnostic imaging system and method are described for performing nonlinear echo signal imaging with sum or difference frequency signal components. The sum or difference frequency components are produced by nonlinear effects of tissue or contrast agents and are advantageously separated from the fundamental transmit components of the echo signals by pulse inversion processing. The transmit frequency components are located at frequencies chosen so that the sum or difference frequency components to be used for imaging fall in the central, most sensitive, region of the transducer passband. The beam profiles of the sum or difference frequency components exhibit improved signal to clutter ratios and lateral resolution characteristics as compared to the transmit beam characteristics.